托福听力

🎧 听力原文

Listen to part of a lecture in an anthropology class. The professor is discussing the role of play in animal behavior. 'Now, many of you probably think of play as just a way for young animals to burn off energy. But research shows it’s much more complex. Take, for example, the play fighting of young rats. When they play, they emit high-frequency vocalizations, which we call laughter. This laughter is not just a byproduct—it seems to signal that the interaction is safe and voluntary. In fact, when one rat stops laughing, the other often stops playing. This suggests that play relies on mutual consent and communication. But why do animals play at all? One theory is that play helps animals develop motor skills and social bonds. Another more recent hypothesis is that play serves as a form of risk assessment. By engaging in mock fights, young animals learn the strengths and weaknesses of their peers without causing serious injury. This information can be crucial later in life, especially for species that live in complex social groups where dominance hierarchies matter. So, play is not trivial—it’s a serious business for survival.'